#include<stdio.h>
#include<string.h>
#include<unistd.h>




int main ()
{
  
  //C语言提供的
  printf("hello world\n");
  const char* s1 = "hello frite\n";
  fwrite(s1, 1, strlen(s1), stdout);
  fprintf(stdout,"hello fprintf\n");

  //OS系统提供的接口
  const char *s2 = "hello write\n";
  write(1, s2, strlen(s2));
  

  //fork();
  return 0;
}
